JP2016013952A - Manufacturing apparatus for crystalline molten slag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing apparatus for crystalline molten slag, the apparatus capable of manufacturing crystalline molten slag excellent in mechanical strength with reduced quality variations, and furthermore requiring a small amount of energy consumption.SOLUTION: Incineration ash is melted in a melting furnace 2 to form an incineration ash molten material 3, then the incineration ash molten material 3 is poured into a slag pan 4, and enters a tunnel chamber 6 by transported by a vehicle. Further, after stayed in the tunnel chamber 6 for a prescribed time, during the time transported out from the other end, radiation heat is received by fins 11 which are disposed in the chamber 6 for cooling the incineration ash molten material by making air flow from the other end or one end of the tunnel chamber to the one end or the other end. A cooling speed of the incineration ash molten material 3 is controlled by controlling a flow rate of the air made flown into the tunnel chamber 6, and the heat of air exhausted from the tunnel chamber 6 is recovered.

Description

  The present invention relates to an apparatus for producing crystalline molten slag and an apparatus for producing crystalline molten slag.

  Landfill disposal of garbage incineration ash may contaminate the environment due to elution of harmful substances. For this reason, waste incineration ash is heated and melted, and generally poured into water to form molten slag. Molten slag has very little elution of heavy metals compared to the waste incineration ash before melting, and the safety is high even if landfill disposal is performed as it is. Moreover, since the volume reduction effect is great, the life of the landfill site can be extended. However, in order to melt the waste incineration ash, a large amount of energy is consumed, so that there is a problem that the cost is too high. This is one factor that hinders the spread of the melting slag processing of the waste incineration ash.

  For this reason, the molten slag is not reclaimed as it is, but reused as an aggregate or a roadbed material. However, granulated slag that has been cooled by introducing incinerated ash melt into water is very brittle with vitrified particles and easily becomes finer. Therefore, the reuse destination is limited to the replacement of fine aggregate. In order to solve these problems in the reuse of molten slag, crystalline molten slag is produced by slowly cooling the incinerated ash melt (slow cooling) or by reheating to 900 ° C to 1,000 ° C. There are proposals (for example, Patent Documents 1 and 2).

JP 2007-314352 A Japanese Patent Laid-Open No. 4-132642

  In the conventional method for producing crystalline molten slag, the incinerated ash melt is placed in an iron container and allowed to cool naturally (Patent Document 1), or the size and shape of the iron container are changed (Patent Document 2), and then incinerated. Controls the cooling rate of the ash melt. However, with such a control method, it is difficult to precisely control the cooling rate of the incinerated ash melt, and the crystallinity and mechanical strength of the produced molten slag vary. On the other hand, when the incinerated ash melt is reheated to 900 ° C. to 1,000 ° C., a large amount of energy is required, resulting in a problem that the energy cost increases.

  The present invention has been made in view of the above-described conventional circumstances, and can produce crystalline molten slag having excellent mechanical strength and low quality variation from the incinerated ash melt, and also having an energy consumption amount of Providing an apparatus for producing a small amount of crystalline molten slag is a problem to be solved.

  The apparatus for producing crystalline molten slag according to the present invention is a crystallization slag producing apparatus for air-cooling incinerated ash melt to form crystalline molten slag, and a tunnel chamber through which a container loaded with incinerated ash melt passes And a fin that is provided in the tunnel chamber and receives radiant heat from the container loaded with the incinerated ash melt, and a blower means for sending air from one end side to the other end side in the tunnel chamber. It is characterized by that.

In the crystalline molten slag manufacturing apparatus of the present invention, when the container loaded with the incinerated ash melt passes through the tunnel chamber, the fins provided in the tunnel chamber are heated by the incinerated ash melt and the radiant heat from the container. . And the air sent from the one end side in the tunnel chamber by the air blowing means performs heat exchange with the fins, and becomes heated air and exits from the other end side of the tunnel chamber. For this reason, heating air can be used as a heat source for drying incinerated ash, and as a result, production energy consumption and production cost of crystalline molten slag can be reduced. Moreover, the cooling rate of the incinerated ash melt can be easily controlled by adjusting the flow rate of the air sent into the tunnel chamber and the residence time of the container passing through the tunnel chamber. For this reason, the crystallinity can be appropriately controlled in accordance with the outside air temperature, and is not affected by the wind. Therefore, it is possible to easily produce a crystalline molten slag having a constant quality and excellent mechanical strength.
The fins preferably have an area and shape sufficient to transfer heat to the air.

  In the crystalline molten slag manufacturing apparatus of the present invention, a drying furnace for drying incinerated ash as a raw material can be provided by heated air discharged from the tunnel chamber. If it is like this, the heat | fever collect | recovered from the incineration ash melt can be utilized for drying of incineration ash, and the energy for manufacturing crystalline molten slag can be saved.

  The crystalline molten slag production apparatus of the present invention can be performed by the crystalline molten slag production apparatus of the present invention. That is, the method for producing crystalline molten slag of the present invention includes a carrying-in step of carrying in a container loaded with incinerated ash melt from one end of a tunnel chamber, and after the carrying-in step, from the other end or one end of the tunnel chamber. A cooling step of cooling the incinerated ash melt into crystalline molten slag by flowing air toward the one end or the other end, and the crystalline molten slag generated by the cooling step from the other end side of the tunnel chamber An unloading step of unloading with the container.

It is a schematic diagram of the manufacturing apparatus of the crystalline molten slag of embodiment. It is process drawing of the manufacturing method of the crystalline molten slag of embodiment. It is a schematic cross section which shows the use condition of the cooling furnace 40 in the manufacturing apparatus of the crystalline molten slag of embodiment. 1 is a schematic cross-sectional view of a cooling test furnace of Example 1. FIG. FIG. 4 is a cross-sectional view of the cooling test furnace of Example 1 taken along the arrow IV-IV. 4 is a graph showing the relationship between time and temperature when forced cooling is performed by an exhaust fan using a cooling test furnace 20. It is a graph which shows the relationship between time and temperature at the time of naturally cooling in air | atmosphere.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings.
The apparatus for producing crystalline molten slag according to the embodiment produces crystalline molten slag from incineration ash of a garbage incineration plant. As shown in FIG. 1, a rotary kiln 1 for drying the garbage incineration ash, and garbage It consists of an electric melting furnace 2 for melting the incinerated ash to form an incinerated ash melt, and a cooling furnace 40 for cooling the incinerated ash melt.
The cooling furnace 40 is provided with a tunnel chamber 6. One end of the tunnel chamber 6 is provided with a carry-in door 7 for carrying the iron slag pan 4 into the tunnel chamber 6, and the other end is provided with a slag pan. An unloading door 10 for unloading 4 from the tunnel chamber 6 is provided. A large number of steel cooling fins 11 are provided on the ceiling 8 of the tunnel chamber 6, and further, an air outlet 12 and an outlet are provided at one end of the ceiling 8 on the carry-out door 10 side and one end on the carry-in door 7 side, respectively. 13 is provided. The blower port 12 is connected to the blower 14, and the discharge port 13 is connected to the air intake 9 of the burner of the rotary kiln 1.

A method for producing crystalline molten slag using the production apparatus of the embodiment configured as described above will be described in the order of steps (see FIG. 2).
<Drying step S1>
As shown in FIG. 1, waste incineration ash WD containing moisture transported from a waste incineration site is put into a rotary kiln 1 to form dry waste incineration ash DD.

<Melting step S2>
Next, the dry waste incineration ash DD is melted in the melting furnace 2 to obtain an incineration ash melt 3. As the main component of garbage incineration ash, CaO, SiO ₂ and Al ₂ O ₃ are usually the main components. When CaO is insufficient, the basicity is adjusted to 0.8 to 1.2 by adding a lime raw material (for example, limestone mineral, slaked lime, and waste containing them) as an auxiliary material. . Examples of the melting furnace include an electric melting furnace (AC arc melting furnace, AC electric resistance melting furnace, DC electric resistance melting furnace, plasma melting furnace, induction melting furnace, etc.) that melts by electric energy, heavy oil Combustion furnace (rotary surface melting furnace, reflective surface melting furnace, radiation surface melting furnace, swirling flow melting furnace, rotary kiln melting furnace, coke bed ash Melting furnaces, etc.), direct melting furnaces (such as coke bed melting furnaces, pyrolysis / swirl-flow melting furnaces, internal melting furnaces, etc.) for directly melting garbage.
The temperature of the melting furnace varies depending on the components of the incinerated ash and may be appropriately selected, but generally melts at 1300 to 1600 ° C.

<Import process S3>
The incinerated ash melt 3 is poured into the slag pan 4 placed on the carriage 4a every predetermined time.
The cart 4a on which the slag pan 4 containing the incinerated ash melt 3 is placed is connected to the transport vehicle 5 and carried from the carry-in door 7, and after the connection is cut off, the carry-in door 7 is closed.

<Cooling step S4>
Next, as shown in FIG. 3A, air is sent from the blower 14 for a predetermined time and enters the tunnel chamber 6 through the blower opening 12. Then, heat exchange is performed between the cooling fins 11 heated by the incinerated ash melt and the radiant heat from the slag pan 4 and the air, and the heated air is discharged from the discharge port 13. And the discharged | emitted heated air is sent to the air intake 9 of the rotary kiln 1 shown in FIG. 1, and the waste incineration ash WD containing a water | moisture content is dried.

<Unloading step S5>
After a lapse of a predetermined time since the slag pan 4 is carried into the tunnel room 6, as shown in FIG. 3 (b), the carry-out door 10 is opened, and the carriage 4a on which the slag pan 4 is placed is connected to the transport vehicle, and the tunnel room. 6 It is carried out of the outside and the top one is cut off.
Furthermore, said carrying-in process S3, cooling process S4, and carrying-out process S5 are repeated.

In the tunnel chamber 6 of the embodiment, the sensible heat of the incinerated ash melt is transmitted to the cooling fins 11 as radiant heat, and is recovered by exchanging heat with the air blown from the blower 14. The amount of heat per time for heat exchange can control the cooling rate of the incinerated ash melt by adjusting the amount of air blown from the blower 14, the size of the slag pan 4, and the residence time in the tunnel chamber 6. it can. For this reason, the crystallinity can be appropriately controlled in accordance with the outside air temperature, and is not affected by the wind. Therefore, it is possible to easily produce a crystalline molten slag having a constant quality and excellent mechanical strength. The cooling rate of the incinerated ash melt is preferably 1 ° C./min or more in the crystal growth temperature range from crystal formation. Further, the heated air recovered by heat exchange with the cooling fins 11 and the like is sent to the air intake 9 of the rotary kiln 1 shown in FIG. 1, and the waste incineration ash WD containing moisture is used for drying. For this reason, the city gas consumption of the burner conventionally used for drying garbage incineration ash WD can be reduced significantly.
The heat balance is calculated as follows.
1) When the incineration ash WD is dried only by city gas combustion using a burner, the result is as follows.
Monthly city gas consumption: 32,000Nm ³ / month city gas calorific value: 41.65MJ / Nm ³
Monthly heat consumption: 32,000Nm ³ × 41.65 MJ / Nm ³ = 1,333,000 MJ / month.
2) The amount of heat recovered from the incinerated ash melt When the incinerated ash melt is cooled from 1350 ° C to 350 ° C, the specific amount of heat is 0.265 cal / g, and the amount of heat recovered from the incinerated ash melt is calculated using the following formula: .
4.18 × 0.265 cal / g × 1000 ° C × 1000t / month × 1000kg / t × 1000g / kg = 1,227,000 MJ / month 3) Heat balance From the above calculation, it is slightly more than the monthly heat consumption by city gas (1333000 MJ / month) Less heat is recovered from the incineration ash melt, and the incineration ash WD can be dried by merely cooking a little city gas to dry the incineration ash WD.

Example 1
In Example 1, the cooling test furnace 20 for heat recovery shown in FIG. 4 was produced, and a heat recovery experiment from the incinerated ash melt was performed. The cooling test furnace 20 is provided with a bottomless quadrangular prism-shaped steel container 21, and the ceiling 21 a of the container 21 has a quadrangular pyramid shape. A hole 22 is opened at the center of the ceiling 21a, and a discharge pipe 23 is connected to the hole 22. The other end of the discharge pipe 23 is connected to an exhaust fan (not shown). A large number of cooling fins 24 are provided radially on the ceiling 21a around the hole 22 (see FIG. 5). In addition, an inlet pipe 25 for taking in outside air is provided at the lower end of the container 21. The container 21 is surrounded by a heat resistant heat insulating material 26.

Using the cooling test furnace 20 configured as described above, a heat recovery experiment from the incinerated ash melt was performed.
First, the incinerated ash melted by the electric melting furnace was put into the slag pan 30, and the cooling test furnace 20 was put on it. And 1) incinerated ash melt center temperature, 2) surface temperature of slag pan, 3) heat insulating material outer surface temperature, and 4) outside air temperature were measured with a thermocouple. For comparison, in the state exposed to the outside air without covering the cooling test furnace 20, 1) the incineration ash melt center temperature, 2) the incineration ash melt surface temperature, 3) the surface temperature of the slag pan, and 4) the outside air The temperature was measured with a thermocouple.

  As a result, when forced cooling is performed by an exhaust fan using the cooling test furnace 20, the temperature of the incinerated ash melt center and the surface temperature of the slag pan are smoothly reduced as shown in FIG. In the case of natural cooling in the atmosphere, as shown in FIG. 7, the temperature at the center of the incinerated ash melt and the surface temperature of the slag pan are not smoothly lowered, and are affected by the outside air temperature and wind. It was considered. In addition, when forced cooling is performed by an exhaust fan, the exhaust fan exhaust speed can be easily controlled by the rotational speed of the exhaust fan, so that the cooling rate of the incinerated ash melt can be easily controlled. I understand. For this reason, it turned out that it is excellent in mechanical strength from an incinerated ash melt, and can manufacture crystalline molten slag with few quality variations. Moreover, since the heated air is discharged | emitted from the discharge pipe 23, this can be utilized as heat sources, such as drying of incineration ash.

  The present invention is not limited to the description of the embodiments of the invention. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

DESCRIPTION OF SYMBOLS 1 ... Rotary kiln, 2 ... Melting furnace, 40 ... Cooling furnace, 3 ... Incinerated ash melt, 6 ... Tunnel room, 4 ... Slag pan, 11 ... Cooling fin (fin), 14 ... Blower (blower means)
S1 ... drying process, S2 ... melting process, S3 ... carrying-in process, S4 ... cooling process, S3 ... unloading process

Claims (3)

A crystallization slag production apparatus for air-cooling incinerated ash melt to form crystalline molten slag,
A tunnel chamber through which a container loaded with the incinerated ash melt passes; a fin provided in the tunnel chamber for receiving radiant heat from the container loaded with the incinerated ash melt; and from one end side to the other end side of the tunnel chamber. An apparatus for producing crystalline molten slag, comprising: air blowing means for sending air toward.   The crystallization slag production apparatus according to claim 1, further comprising a drying furnace for drying the incinerated ash by the heated air discharged from the tunnel chamber. A carrying-in process of carrying a container loaded with incinerated ash melt from one end of the tunnel room;
A cooling step of cooling the incinerated ash melt into crystalline molten slag by flowing air from the other end or one end of the tunnel chamber toward the one end or the other end after the carrying-in step;
A method for producing crystalline molten slag, comprising: carrying out the crystalline molten slag generated by the cooling step together with the container from the other end of the tunnel chamber.

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